Both obesity and type 2 diabetes mellitus (T2DM) are global public health problems and their prevalence will increase dramatically over the coming decades. The rise in obesity has been matched by a rise in diabetes in all ethnic groups in the United States (Caterson et al. Circulation. 2004; 110:e476-483). The Third National Health and Nutrition Examination Survey (National Task Force on the Prevention and Treatment of Obesity. Overweight, obesity, and health risk, Arch Intern Med. 2000; 160:898-904) found that approximately two thirds of adult men and women in the United States diagnosed with type 2 diabetes have a body mass index of 27 or greater. It has been well known that a core characteristic of patients with obesity and T2DM is an increase in insulin resistance, while many studies have indicated that intramyocellular accumulation of triglycerides is a major contributor to insulin resistance (Goodpaster & Wolf, Pediatr Diabetes. 2004; 5:219-226). Interestingly, mitochondrial dysfunction may predispose an individual to intramyocellular lipid accumulation. However, due to the limited protein coding capacity of mitochondria, the initiation and regulation of mitochondrial biogenesis rely heavily on ˜1000 nucleus encoded mitochondrial regulatory proteins (DiMauro, Mitochondrion. 2004; 4:799-807). The majority of mitochondrial proteins are nuclear encoded, synthesized in the cytosol, and are post-translationally imported into mitochondria. Therefore, most inherited mitochondrial diseases are reported due to mutations in nucleus-encoded mitochondrial genes.
Among a large number of reactions occurring in mitochondria, probably the most impressive of these is oxidative phosphorylation, in which five multi-subunit complexes cooperate to generate most of the cell's energy. Among them, the ubiquinol-cytochrome c reductase complex or complex III is an oligomeric enzyme that catalyzes transfer of electrons from coenzyme QH2 to ferricytochrome c with the coupled translocation of protons across the mitochondrial inner membrane (Brandt & Trumpower, Crit Rev Biochem Mol Biol. 1994; 29:165-197). The bovine heart mitochondrial complex III has been well characterized, which is composed of 11 subunits, including 10 nuclear-encoded subunits and 1 mitochondrial-encoded subunit (Iwata et al. Science. 1998; 281:64-71).
There is a need for methods that allow relatively easy and more efficient selection and breeding of farm animals that have an advantageous fat deposition and fatty acid composition. The economic significance of the use of genetic markers that are associated with specific economically important traits (especially carcasses and meat quality traits that are hard to measure) in livestock through marker-assisted selection cannot therefore be overemphasized.
Citation or identification of any document in this application is not an admission that such document is available as prior art to the present invention.